Uh, ShareCoin was a service or feature of blockchain. It wasn't exactly a CoinJoin implementation. JoinMarket does CoinJoin, but I understand why you'd want an easier method.

Which leads me to ask: What qualifies for the bounty? There's 42 BTC up for grabs on the bounty multi-sig address, but JoinMarket doesn't seem to qualify, or maybe it's not considered "practical" enough.

If I make a website that looks like, for example, shapeshift, and you see that you can send coins there, and every hour there is a CoinJoin transaction (even if internal to the site), does that count? Or any form of centralization doesn't count?

See, for CoinJoin to really work the way it was intended, everyone that participates in a CoinJoin transaction needs to be all online and they all need to sign. Perhaps what they're looking for is some Windows Bitcoin Core Qt wallet type that includes a tick box for [X] CoinJoin, then it would automatically look for others.

Uh, ShareCoin was a service or feature of blockchain. It wasn't exactly a CoinJoin implementation. JoinMarket does CoinJoin, but I understand why you'd want an easier method.

Which leads me to ask: What qualifies for the bounty? There's 42 BTC up for grabs on the bounty multi-sig address, but JoinMarket doesn't seem to qualify, or maybe it's not considered "practical" enough.

If I make a website that looks like, for example, shapeshift, and you see that you can send coins there, and every hour there is a CoinJoin transaction (even if internal to the site), does that count? Or any form of centralization doesn't count?

See, for CoinJoin to really work the way it was intended, everyone that participates in a CoinJoin transaction needs to be all online and they all need to sign. Perhaps what they're looking for is some Windows Bitcoin Core Qt wallet type that includes a tick box for [X] CoinJoin, then it would automatically look for others.

I'm curious as to WHY it was a service that is no longer? Who shut it down? Is the code still out there?

There were 3 people involved in the transaction. There are 6 outputs, 2 per person. 3 of the outputs (coloured yellow) are for the exact same amount. It's impossible to know which of these three yellow outputs belongs to which of the 3 people just from looking at this transaction. The other 3 outputs are change amounts. We can easily tie the change outputs to the inputs, which I did by using the coloured arrows.

The guy who spent 82 BTC got back a yellow 70 BTC and 12 BTC of change - indicated by the blue arrow.The guy who spent 171 BTC got back a yellow 70 BTC and 101 BTC of change - indicated by the orange arrow.All the other inputs came from the 3rd guy, and he got back a yellow 70 BTC and 41 BTC of change - indicated by all the red lines.

Hopefully that makes it clearer. It's the yellow outputs that have been anonymised by this transaction, not the inputs or the change outputs.

Cool, I first thought that inputs are sent to another bitcoin address and from there to the outputs. But, this seems not to be the case. Is CoinJoin a smart contract or a dAPP as with Ethereum?